Trigger Point Injection Periprocedural Care

Patients should rest the affected areas for 1-2 days after the injections. Strenuous activities should be avoided for at least the period of postinjection muscle soreness. However, the patient is encouraged to use the muscle with full range of motion rather than hold the muscle in a fixed, shortened position. ^[2]

The patient must learn to recognize the pain-provoking activities and movements that overstress the muscles. Such activities should be avoided or modified to achieve lasting relief from myofascial pain. Patients must learn the limitations of their own muscles and use proper body alignment and body mechanics. Common problems with exercise include overenthusiasm, performing activities despite exhaustion or pain, and using an incorrect technique.

The needle size is important for precise injection. A 22-gauge 3.8-cm (1.5 in.) needle is used for superficial muscles. When capillary fragility with bleeding is a concern, a thinner 25-gauge needle may be preferred. In thick subcutaneous muscles, at least a 21-gauge 5-cm (2-in.) needle is needed.

The needle should never be inserted to its full length, because of the risk of breaking off. A 21-gauge 7.6-cm (3-in.) needle is generally long enough to reach trigger points in the deepest muscles, but occasionally a 8.9-cm (3.5-in.) 22-gauge spinal needle is needed. Because of the excessive flexibility of the spinal needle, it is important to keep the needle straight.

The basic equipment for trigger point injections includes, but is not limited to, the following ^[2] :

• Needles and syringes of various sizes
• Povidone-iodine solution or alcohol
• Sterile gauze pads
• Gloves (need not be sterile)
• Lidocaine
• Isotonic saline
• Vapocoolant spray
• Bandages

The following needles may be used:

• Withdrawal of anesthetic solution - 16-gauge 1.5-in. needle
• Scalenus, sternocleidomastoid, and interossei: 22- to 25-gauge 1.5-in. needle
• Temporomandibular joint muscles - 25-gauge 1.5-in. needle
• Cervical and suboccipital areas, upper extremities, and ankle and foot - 22-gauge 1.5-in. needle
• Extremities - 21-gauge 2.0-in. needle
• Lumbar and gluteal areas - 20- to 21-gauge 3-in. needle
• Gastrocnemius - 25-gauge 2.0-in. needle

Anesthesia

Solutions for injections include 0.5% procaine, 1% lidocaine, and isotonic saline. Isotonic saline or dry needling may be used in patients allergic to local anesthetics. Steroids may be used for ligamentous trigger points. Long-acting anesthetics (eg, bupivacaine) have also been used. ^[2]

Several other substances, including diclofenac, onabotulinumtoxinA, and corticosteroids, have been used in trigger point injections. However, these substances are associated with significant myotoxicity. Procaine is the least myotoxic of all local injectable anesthetics.

Positioning

Have the patient lie down (prone or supine) if possible. Injections may be done in a seated position as well. The patient may be placed in a recumbent position to avoid psychological syncope and to facilitate relaxation for easier localization of the trigger points.